Semiconductor Package with a Mold Material Encapsulating a Chip and a Portion of a Lead Frame

ABSTRACT

Various exemplary embodiments provide components, devices, and methods of semiconductor packaging. The disclosed packaging component can include a mold material disposed around a lead frame and at least an integrated circuit (IC), wherein the IC is electrically connected with one side of the lead frame. The opposite side of the lead frame including, for example, lead segments, can be exposed from the mold material. A variety of other components, devices, and packages can then be assembled, e.g., over the disclosed packaging component, through the exposed regions so as to improve packaging densities.

RELATED APPLICATIONS

This is a divisional of application Ser. No. 12/411,713 filed Mar. 26,2009 and claims priority from U.S. Provisional Patent Application Ser.No. 61/105,288, filed Oct. 14, 2008, which is hereby incorporated byreference in its entirety.

DESCRIPTION OF THE INVENTION

1. Field of the Invention

The present invention relates generally to the field of semiconductordevice packaging, and more specifically to device packaging over a moldmaterial.

2. Background of the Invention

A lead frame-based semiconductor device package is the most widely usedintegrated circuit (IC) package. The lead frame typically includes achip mount pad (also referred to as a die paddle) for attaching the ICdie or chip to the leadframe, and a plurality of lead fingers orconductive segments (pins) which provide a conductive path between thechip and external circuits. A gap between the inner end of the leadfingers and the chip is typically bridged with bond wires attached tobond pads on the chip and to the inner end of the lead fingers. Theouter ends of the lead fingers remote from the IC chip can beelectrically and mechanically connected to external circuitry.

The packaged IC may include semiconductor chips and their associatedcomponents, such as passive components or the like embedded within themold material. The packaged integrated circuits are connected orsoldered to a printed circuit board (PCB) of an electric device. Passivecomponents or the like must be placed inside the package so that theycan be located on the lead frame inside the mold material. Through theprinted circuit board, the packaged integrated circuit may be connectedto other chips and to external inputs and outputs.

SUMMARY OF THE INVENTION

The Applicant has discovered that assembling related components outsidethe mold material of a packaged component has advantages overconventional methods that assemble related components inside the moldmaterial. In various embodiments, this can be accomplished by exposingor extending one or more lead frame fingers (also referred to herein aslead segments) outside the mold material of a lead-frame-based ICpackaging component, such that related components can be packaged overthe mold material rather than inside the mold material.

In one embodiment, the disclosed IC packaging component can include oneor more IC chips, for example, wire-bonded or flip-chipped, on one sideof the lead frame, while other related components, such as passivecomponents or the like, can be connected or fixed to the opposite sideof the lead frame. In this manner, a more efficient utilization of thelead frame can be provided as compared with conventional lead framebased IC packages, where the IC chips and related components arepackaged within the mold material and on the same side of the leadframe.

Various related components, such as, for example, passive components,printed circuit boards (PCBs), ball grid arrays (BGAs), other ICs, otherpackaging components, or combinations thereof, can be packaged in avertical direction over the IC packaging component through the exposedregions thereof to provide a high packaging density.

In various embodiments, the related components, which are directly orindirectly associated with the IC chips of the packaging component, canbe assembled over the exposed lead frame segments, so as to improvepackage densities. In an exemplary embodiment, a second IC chip can beattached to the top of IC packaging component facing up with asubsequent BGA package attached thereto. In another exemplaryembodiment, a combination of laminated PCB, BGA, other ICs, and passivecomponents can be attached on top of the IC packaging component tocommunicate with the integrated circuit of the packaging component.

It is a technical advantage of various embodiments of the invention thatexposing lead segments out from a mold material of a packaging componentprovides a high packaging density method for assembling a variety ofcomponents with the IC packaging component.

The technical advances represented by the invention, as well as theaspects thereof, will become apparent from the following description ofthe preferred embodiments of the invention, when considered inconjunction with the accompanying drawings and the novel features setforth in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description, serve to explain the principles of theinvention. In the figures:

FIG. 1 is a schematic cross section depicting a first embodiment of theinvention of semiconductor packaging in accordance with the presentteachings;

FIG. 2 is a schematic cross section depicting a second embodiment of theinvention using the semiconductor package of FIG. 1 in accordance withthe present teachings;

FIG. 3 is a schematic cross section depicting a third embodiment of theinvention using the semiconductor package of FIG. 1 in accordance withthe present teachings;

FIG. 4 is a schematic cross section depicting a forth embodiment of theinvention using the semiconductor package of FIG. 1 in accordance withthe present teachings;

FIG. 5 is a schematic cross section depicting a fifth embodiment of theinvention using the semiconductor package of FIG. 1 in accordance withthe present teachings; and

FIG. 6 is a schematic cross section depicting a sixth embodiment of theinvention using the semiconductor package of FIG. 1 in accordance withthe present teachings.

It should be noted that some details of the FIGS. have been simplifiedand are drawn to facilitate understanding of the inventive embodimentsrather than to maintain strict structural accuracy, detail, and scale.

DESCRIPTION OF THE EMBODIMENTS

The Applicant has realized that new packaging devices and methods areneeded to improve the packaging density for the IC industry. Referencewill now be made in detail to exemplary embodiments of the invention,examples of which are illustrated in the accompanying drawings. Whereverpossible, the same reference numbers will be used throughout thedrawings to refer to the same or like parts.

Various exemplary embodiments provide components, devices, and methodsof semiconductor packaging. The disclosed packaging component caninclude a mold material, disposed around a lead frame and at least anintegrated circuit (IC), wherein the IC is electrically connected withone side of the lead frame. The opposite side of the lead frameincluding, for example, lead segments, can be exposed or extended fromthe mold material. A variety of other related components, devices, andpackages can then be assembled, e.g., on top of the disclosed packagingcomponent (rather than within the mold material as known in the priorart), through the exposed lead segments so as to improve packagingdensities. The lead frame can also include external lead pins extendingoutside the mold material for an external connection as known to one ofordinary skill in the art.

As used herein, the term “related components” or “other relatedcomponents” refers to all possible components or devices that need to bepackaged with the components in the mold material, for example, whichcan include at least an IC in the mold material. The “relatedcomponents” can include, but are not limited to, passive components,printed circuit boards (PCBs), ball grid arrays (BGAs), other ICs, otherpackaging components, or combinations thereof.

As used herein, the term “lead segments” or “lead frame segments” refersto a first set of one or more portions or fingers of the lead frame,wherein the “lead segments” are exposed or extended from the moldmaterial and are accessible from a vertical direction for packagingsubsequently with various “related components”. In various embodiments,the exposed “lead segments” can allow the vertically packaged “relatedcomponents” and the exemplary IC in the mold material to be packaged onopposite sides of the lead frame.

As used herein, the term “vertical direction” refers to a direction thatis about normal to a surface of the mold material. For example, variousrelated components can be packaged, in a vertical direction that is ontop of the mold material, with the IC located in the mold material. Invarious embodiments, the “vertical direction” also refers to a directionthat is about normal to a substrate (e.g., a wafer surface) of theexemplary IC packaged in the mold material.

As used herein, the term “lead pins” or “external lead pins” refers to asecond set of one or more portions or fingers of the lead frame, whereinthe “lead pins” are extended outside the mold material for an externalconnection, for example, to a printed circuit board (PCB). Through thePCB, the packaged IC can be connected to, for example, external inputsand outputs, as known to one of ordinary skill in the art.

FIG. 1 is a schematic cross section depicting an exemplary IC packagingcomponent 100 in accordance with the present teachings. The IC packagingcomponent 100 can include a mold material 110, an IC 120, a lead frame130, and wire bonds 140. It should be readily apparent to one ofordinary skill in the art that the component 100 depicted in FIG. 1represents a generalized schematic illustration and that othercomponents/devices can be added or existing components/devices can beremoved or modified.

As shown, the IC 120 can be wire bonded to the lead frame 130 by thewire bonds 140, while the IC 120, a portion of the lead frame 130 andthe wire bonds 140 can be held in position by the mold material 110.Note that although one integrated circuit IC is shown in FIG. 1, one ofordinary skill in the art will understand that a plurality of ICs aswell as other related components can be disposed in the mold material110. In addition, while the wire bonds are used for connecting IC 120 tothe lead frame 130, various other connections can be used for packagingcomponent 100. For example, the IC 120 can be flip-chip mounted onto thelead frame 130.

The integrated circuit 120, alone or in combination with other relatedcomponents, can include a variety of different features, including, butnot limited to, analog and/or digital circuits such as digital to analogconverters, computer processor units, amplifiers, digital signalprocessors, controllers, transistors, or other semiconductor features.The integrated circuit 120 can include a variety of materials includingsilicon, gallium arsenide, or other suitable materials.

The integrated circuit 120 can be connected with the lead frame 130,e.g., on one side of the lead frame 130, through the bond wires 140. Inone embodiment, the bond wires 140 can conductively bridge an inner sideof the lead frame 130 with the IC 120, e.g., by attaching to a bond pad(not shown) on the IC 120. Bond wires can be formed from variousmaterials, such as gold, copper, aluminum, or other conductive materialsas known to one of ordinary skill in the art.

The lead frame 130 can have a portion assembled inside the mold material110 and can further have a plurality of portions or fingers including,for example, the lead frame segments 132 exposed from the mold material110 for a further packaging process. The lead frame 130 can also includeexternal lead pins 137 protruded from the mold material 110 for externalelectrical connections.

For example, the lead frame 130 can include one or more lead framesegments 132 exposing the other side (e.g., opposite to the wire bondedside) of the lead frame 130 from the mold material 110 to the outside.Other components including for example, passive components, printedcircuit boards (PCBs), ball grid arrays (BGAs), other ICs orcombinations thereof, which are conventionally packaged in the moldmaterial, can then be assembled over the exposed side of the lead frame130 to provide a high packaging density.

The lead frame 130 can also include a plurality of external lead pins137. The external lead pins 137 can be an extension of the lead frame130. In various embodiments, the outer ends of the external lead pins137 remote from the IC 120 can be electrically and mechanicallyconnected to external circuits. For example, the external lead pins 137can extend outside of the mold material 110 or the packaging component100 and can be utilized to establish connections between the packagingcomponent 100 and, for example, a circuit board, when the semiconductorpackaging component 100 is mounted to the circuit board. The lead frame130 can therefore provide a conductive path between the IC 120 andexternal circuits through the lead pins 137.

During manufacture of the integrated circuit packaging component 100,the IC 120 and other components, if there are any, can be connected to(e.g., wire bonded or flip-chipped) the lead frame 130. For example, theIC 120 can be wire bonded to the lead frame 130 using wire bondconnections 140. After assembly of the IC chip 120 to the lead frame130, the mold material 110 can be placed around the IC 120, the bondingwires 140, and a portion of the lead frame 130. One suitable moldingprocess can include an injection molding process. However, othersuitable molding processes including, for example, transfer molding orcasting can be utilized to place mold material around the components.During molding, the portion of the lead pins 137 can be left extendingoutside of the mold material 110 to establish connections with externalcomponents.

In various embodiments, a removable substrate (not shown) can be usedduring the packaging process. For example, the IC 120 and/or othercomponents, and the lead frame 130 can be first placed on the substrate,e.g., a polyimide-based adhesive or tape. After connecting the IC 120and the lead frame 130, the molding process can be conducted to placethe mold material 110 around these components in order to form thepackaging component 100 as shown in FIG. 1. After the molding process,the substrate can be removed to leave the component 100.

The mold material 110, which surrounds and holds the integrated circuit120, the lead frame 130 and the wire bonds 140 in position, can include,for example, transfer molding compounds incorporating fused silicaparticles or castable compounds.

In various embodiments, the exposed regions of the packaging component100, i.e., the top ends of the exposed lead frame segments 132, canprovide a variety of subsequent packaging platforms for a high devicedensity. FIGS. 2-6 depict various exemplary embodiments for subsequentpackaging using the package component and method described for FIG. 1 inaccordance with the present teachings.

FIG. 2 depicts a first example for semiconductor packaging using thecomponent and method shown in FIG. 1 in accordance with the presentteachings. As shown, the packaged device 200 can include one or morepassive components 220 assembled on top of the packaging component 100.Passive components and the like are often assembled inside the moldmaterials along with IC devices as known in the prior art. By assemblingpassive components and/or other related components on top of thepackaging component 100 through the exposed lead frame segments, variouscomponents and/or devices can be packaged vertically, thereby providinghigh packaging densities.

In various embodiments, a plurality of connection contacts can be usedfor the disclosed packaging. For example, as shown in FIG. 2, theconnection contacts can include contacts 150 for the IC 120 and for theexposed lead frame segments 132 and external lead pins 137 to facilitaterelated electrical connections. In various embodiments, the connectioncontacts can include, e.g., a layer of one or more metals including, butnot limited to, copper, aluminum, gold, silver, nickel, tin, platinum,or combinations thereof. The connection contacts can include laminated,plated metal(s) and/or patterned metal layer(s). In various embodiments,the connection contacts can include one or more circuit traces (notshown) radiating outward from the packaging component. In oneembodiment, the connection contacts can be a copper pad having acombination of copper, nickel and gold. In another embodiment, theconnection contacts can be a conduct pad having a combination of nickel,palladium, and gold.

In various embodiments, the lead frame 130 including the lead framesegments 132 and the external lead pins 137can be flood-plated with oneor more metals described above, wherein the plated metal(s) can bepresent everywhere (not illustrated in the figures) on all the portionsof the lead frame.

The passive components 220 can include, but are not limited to,capacitors, inductors, or resistors. The passive component 220 can beelectrically connected with the integrated circuit 120 through theexposed lead frame segments 132 along with the wire bonds 140 positionedbetween the IC 120 and the lead frame 130. Accordingly, the passivecomponents 220 can include a wire bond termination 225 as shown in FIG.2. In various embodiments, the passive component 220 can also beconnected with the IC contacts 150 through one wire bond termination 225so as to communicate with the IC 120.

FIG. 3 depicts a second example for semiconductor packaging using thecomponent and method shown in FIG. 1 in accordance with the presentteachings. The packaged device 300 can include an exemplary ball gridarray (BGA) package structure 330 assembled on top of the packagingcomponent 100.

For example, the BGA package structure 330 can include a substrate usedas a chip carrier, wherein an IC chip (also referred to as a BGA ICchip) (not shown) can be arranged on one surface (e.g., top surface) ofthe substrate to electrically connect a conductive structure, and aplurality of solder balls, e.g., the balls 335, can be mounted on theopposite surface of the substrate to electrically connect the conductivestructure. The solder balls 335 can further be mounted on other electriccomponents, such as the packaging component 100, through the conductivestructure and the solder balls.

In the illustrated example, the solder balls 335 can be electricallyconnected with, e.g., the exposed lead frame segments 132, and thuscommunicate with the IC 120 through bond wires 140. In variousembodiments, as shown in FIG. 3, any BGA structures known to one ofordinary skill in the art can be packaged on top of the packagingcomponent 100 to communicate with the IC 120 through the solder balls335 and the exposed lead frame segments 132. For example, the solderballs 335 can be small eutectic solder balls that are generally about0.012 inch in diameter and generally formed of a lead/tin alloy as knownin the prior art.

FIG. 4 depicts a third example for semiconductor packaging using thecomponent and method shown in FIG. 1 in accordance with the presentteachings. As shown, the packaged device 400 can include a second ICchip 420 and a BGA package 430 vertically packaged on top of the packagecomponent 100 of FIG. 1. In various embodiments, the BGA package 430 canbe similar to the package 330 as shown in FIG. 3.

The second IC chip 420 can be situated over the packaging component 100,or over the integrated circuit 120. The BGA package 430 can beassembled, e.g., on top of the second IC chip 420. The BGA package 430can include solder balls (see for example 435/437) attached or placed ona substrate surface by soldering the balls to a layer (see for example432) of, e.g., gold/nickel/copper. The BGA package 430 can beelectrically connected to the second IC chip 420 though the solder balls435 that are attached to bond pads 425 of the second IC chip 420. TheBGA package 430 can be further electrically connected to the IC 120through solder balls 437 connected to the exposed lead segments 132 andthe bond wires 140.

FIG. 5 depicts a forth example for semiconductor packaging using thecomponent and method shown in FIG. 1 in accordance with the presentteachings. The packaged device 500 can include, e.g., a printed circuit510, a second IC 520, a passive component 526 and a BGA structure 530assembled on top of the packaged component 100 of FIG. 1.

As shown, the printed circuit 510 can be laminated on top of thepackaged component 100. On top of the printed circuit 510, the passivecomponent 526 and the second IC 520 can be assembled and electricallyconnected with the printed circuit 510. The BGA structure 530 can bedisposed over the passive component 526 and/or the second IC 520. Inaddition, the BGA structure 530 can be electrically connected to the IC120 through solder balls 537 and the exposed lead segments 132. The BGAstructure 530 can also be electrically connected with the second IC chip520 through solder balls 535. In various embodiments, any suitableelectrical connections between the elements/components can be used forthe packaging devices as disclosed herein.

FIG. 6 depicts a fifth example for semiconductor packaging using thecomponent and method shown in FIG. 1 in accordance with the presentteachings. The packaged device 600 can include, e.g., passive components620 along with a second package structure 650 assembled on top of thepackaging component 100.

As shown, the passive component 620 can be electrically connected to theIC 120 through its termination 625. The passive component 620 can alsobe electrically connected with the exposed lead segments 132 along withbond wires 140 to communicate with the IC 120 of the packaging component100.

The second package structure 650 can be, e.g., a second lead frame basedpackage structure having a plurality of external lead pins 637electrically connected to an IC chip 620 through bond wires 640. Theexternal lead pins 637 can be an extension of a lead frame in thepackage 650 and can be electrically and mechanically connected to thepackaging component 100. For example, the external lead pins 637 canextend outside of a mold material 610 to establish electricalconnections between the IC chip 620 and the IC 120 through the exposedlead segments 132 and bond wires 140. In various embodiments, the secondpackage structure 650, having the second IC chip 620, bond wires 640,and a portion of lead frame held in the mold material 610, can besimilar to the package component 100. Likewise, a plurality of packagingcomponents 100 can be assembled vertically through the exposed leadsegments 137.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the invention are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. Any numerical value, however, inherently contains certainerrors necessarily resulting from the standard deviation found in theirrespective testing measurements. Moreover, all ranges disclosed hereinare to be understood to encompass any and all sub-ranges subsumedtherein. For example, a range of “less than 10” can include any and allsub-ranges between (and including) the minimum value of zero and themaximum value of 10, that is, any and all sub-ranges having a minimumvalue of equal to or greater than zero and a maximum value of equal toor less than 10, e.g., 1 to 5. In certain cases, the numerical values asstated for the parameter can take on negative values. In this case, theexample value of range stated as “less that 10” can assume negativevalues, e.g. −1, −2, −3, −10, −20, −30, etc.

While the invention has been illustrated with respect to one or moreimplementations, alterations and/or modifications can be made to theillustrated examples without departing from the spirit and scope of theappended claims. In addition, while a particular feature of theinvention may have been disclosed with respect to only one of severalimplementations, such feature may be combined with one or more otherfeatures of the other implementations as may be desired and advantageousfor any given or particular function. Furthermore, to the extent thatthe terms “including,” “includes,” “having,” “has,” “with,” or variantsthereof are used in either the detailed description and the claims, suchterms are intended to be inclusive in a manner similar to the term“comprising.” The term “at least one of” is used to mean one or more ofthe listed items can be selected.

Further, in the discussion and claims herein, the term “on” used withrespect to two materials, one “on” the other, means at least somecontact between the materials, while “over” means the materials are inproximity, but possibly with one or more additional interveningmaterials such that contact is possible but not required. Neither “on”nor “over” implies any directionality as used herein. The term “about”indicates that the value listed may be somewhat altered, as long as thealteration does not result in nonconformance of the process or structureto the illustrated embodiment. Finally, “exemplary” indicates thedescription is used as an example, rather than implying that it is anideal.

Other embodiments of the invention will be apparent to those skilled inthe art from consideration of the specification and practice of theinvention disclosed herein. It is intended that the specification andexamples be considered as exemplary only, with a true scope and spiritof the invention being indicated by the following claims.

1. A method for packaging comprising: connecting one or more componentswith a lead frame, wherein the one or more components comprise at leastan integrated circuit; and molding a mold material around the integratedcircuit and the lead frame to form a packaging component, such that oneor more lead segments of the lead frame are exposed from the moldmaterial for a subsequent vertical packaging and one or more externallead pins of the lead frame extend outside of the mold material for anexternal connection.
 2. The method of claim 1, further comprising a wirebonding or a flip-chip mounting for the connection of the one or morecomponents with the lead frame.
 3. The method of claim 1, furthercomprising packaging one or more passive components over the packagingcomponent, wherein each passive component is electrically connected withthe integrated circuit (IC) through the exposed lead segments.
 4. Themethod of claim 1, further comprising packaging a ball grid array (BGA)structure over the packaging component, wherein the BGA structure iselectrically connected with the integrated circuit (IC) through aplurality of solder balls and the exposed lead segments.
 5. The methodof claim 1, further comprising packaging one or more of a ball gridarray (BGA) structure and a second IC chip over the packaging component;wherein the second IC chip is disposed over the packaging component; orthe BGA structure is electrically connected with the second IC chipthrough a first plurality of solder balls and is electrically connectedwith the integrated circuit in the packaging component through a secondplurality of solder balls and the exposed lead segments.
 6. The methodof claim 1, further comprising packaging one or more of a ball gridarray (BGA) structure, a passive component, a second IC chip and aprinted circuit over the packaging component.
 7. The method of claim 6,further comprising laminating the printed circuit over the packagingcomponent; disposing the passive component over the printed circuit andelectrically connecting the passive component with the printed circuit;disposing the second IC chip over the printed circuit and electricallyconnecting the second IC chip with the printed circuit; connecting theBGA structure with the printed circuit through a first plurality ofsolder balls; and connecting the BGA structure with the integratedcircuit in the packaging component through a second plurality of solderballs and the exposed lead segments.
 8. The method of claim 1, furthercomprising packaging one or more of a lead frame based packagingcomponent and a passive component over the mold material, wherein eachof the lead frame based packaging component and the passive component iselectrically connected with the integrated circuit through the exposedlead segments.